A satellite of mass m is circulating around the earth with constant angular velocity. If radius of the orbit is R0 and mass of the earth M, the angular momentum about the centre of the earth is (a) m√GMR0 …
The largest and the shortest distance of the earth from the sun are r1 and r2 , its distance from the sun when it is at the perpendicular to the major axis of the orbit drawn from the sun (a) …
A metal bar of length L and area of cross-section A is clamped between two rigid supports. For the material of the rod, its Young’s modulus is Y and coefficient of linear expansion is . If the temperature of the …
Two planets move around the sun. The periodic times and the mean radii of the orbits are T1 , T2and r1 ,r2 respectively. The ratio T1/T2 is equal to (a) ( r1 /r2 )1/2 …
A copper wire of length 4.0m and area of cross-section 1.2 cm2 is stretched with a force of 4.8×103N. If Young’s modulus for copper is .2×1011 N/m2 the increase in the length of the wire will be (a) 1.33 mm …
A planet moves around the sun. At a given point P, it is closest from the sun at a distance d1 and has a speed v1 . At another point Q, when it is farthest from the sun at a distance …
If the interatomic spacing in a steel wire is 3.0Å and Ysteel =20×1010 N/m2 then force constant is (a) 6×10-2 N/Å (b) 6×10-9 N/Å (c) 4×10-5 N/Å (d) 6×10-5 N/Å Answer-b (19)
The earth revolves about the sun in an elliptical orbit with mean radius 9.3 × 107 in a period of 1 year. Assuming that there are no outside influences (a) The earth’s kinetic energy remains constant (b) The earth’s angular …
The figure shows the motion of a planet around the sun in an elliptical orbit with sun at the focus. The shaded areas A and B are also shown in the figure which can be assumed to be equal . …
c HCl molecule about an axis passing through its centre of mass and perpendicular to the line joining the H+ and Cl– ions will be, if the interatomic distance is 1 Å (a) 0.641 x 10-47 kg.m2 (b) 1.61 x …
The distance of neptune 1013 and 1012 saturn from sun are nearly and meters respectively. Assuming that they move in circular orbits, their periodic times will be in the ratio (a) √10 …
When a satellite going round the earth in a circular orbit of radius r and speed v loses some of its energy, then r and v change as (a) r and v both with increase (b) r and v both …
In planetary motion the areal velocity of position vector of a planet depends on angular velocity (ω) and the distance of the planet from sun (r). If so the correct relation for areal velocity is Answer: c (8)
Two planets at mean distance d1 and d2 from the sun and their frequencies are n1 and n2 respectively then Answer: b (11)
Potential energy of a satellite having mass ‘m’ and rotating at a height of 6.4 × 106m from the earth surface is (a) -0.5 mgRe (b) -mgRe (c) -2 …
A satellite with kinetic energy Ek is revolving round the earth in a circular orbit. How much more kinetic energy should be given to it so that it may just escape into outer space (a) Ek (b) 2 Ek …
If the gravitational force between two objects were proportional to 1/R (and not as 1/R2) where R is separation between them, then a particle in circular orbit under such a force would have its orbital speed v proportional to (a) …
Distance of geostationary satellite from the surface of earth radius (Re =6400 km )in terms of Re) is (a) 13.76 Re (b) 10.76 Re (c) 6.56 Re …
The distance between centre of the earth and moon is 384000 km. If the mass of the earth is 6 ×1024 kg and G = 6.66 × 10-11Nm2/kg2. The speed of the moon is nearly (a) 1 km/sec (b) …
Given radius of Earth ‘R’ and length of a day ‘T’ the height of a geostationary satellite is [G–Gravitational Constant, M–Mass of Earth] Answer: c (9)
The orbital speed of an artificial satellite very close to the surface of the earth is V° . Then the orbital speed of another artificial satellite at a height equal to three times the radius of the earth is (a) …
On applying a stress of 20×108 N/m2 the length of a perfectly elastic wire is doubled. Its Young’s modulus will be (a) 40×108 N/m2 (b) 20×108 N/m2 (c) 10×108 N/m2 (d) 5×108 N/m2 Answer-b (7)
How much force is required to produce an increase of 0.2% in the length of a brass wire of diameter 0.6 mm (Young’s modulus for brass =0.9×1011 N/m2 ) (a) Nearly 17 N …
A 5 m long aluminium wire ( Y=7×1010 N/m2) of diameter 3 mm supports a 40 kg mass. In order to have the same elongation in a copper wire ( Y=12×1010 N/m2) of the same length under the same weight, the …
Two similar wires under the same load yield elongation of 0.1 mm and 0.05 mm respectively. If the area of cross- section of the first wire is 4mm2 then the area of cross section of the second wire is (a) …
A steel wire of lm long and cross section area is 1mm2 hang from rigid end. When weight of 1kg is hung from it then change in length will be (given Y=2×1011N/m2) (a) 0.5 mm (b) 0.25 mm (c) …
Three rings each of mass M and radius R are arranged as shown in the figure. The moment of inertia of the system about YY’ will be (a) 3 MR2 (b) 3/2 MR2 (c) 5 MR2 (d) 7/2 MR2 Ans. d …
Four thin rods of same mass M and same length l, form a square as shown in figure. Moment of inertia of this system about an axis through centre O and perpendicular to its plane is (a) 4/3 Ml2 (b) …
A circular disc X of radius R is made from an iron plate of thickness t, and another disc Y of radius 4R is made from an iron plate of thickness t/4 . Then the relation between the moment of …
Two satellites of masses m1 and m2( m1>m2 ) are revolving round the earth in circular orbits of radius r1 and r2( r1>r2 ) Which of the following statements is true regarding their speeds v1 and v2 ? (a) v1 …
A rubber pipe of density 1..5×103 N/m2 and Young’s modulus is 5×106 N/m2 suspended from the roof. The length of the pipe is 8 m. What will be the change in length due to its own weight (a) 9.6 m …
A rod is fixed between two points at 20°C. The coefficient of linear expansion of material of rod is 1.1×10-5/°C and Young’s modulus is 1.2×1011 N/m2 . Find the stress developed in the rod if temperature of rod becomes 10°C …
The coefficient of linear expansion of brass and steel are α1 and α2 . If we take a brass rod of length l1 and steel rod of length l2 at 0°C, their difference in length (l2-l1) will remain the same at …
A wire of cross-sectional area is 3mm2 first stretched between two fixed points at a temperature of 20°C. Determine the tension when the temperature falls to 10°C. Coefficient of linear expansion α=10-5 °C-1 and Y=2×1011 N/m2 (a) 20 N (b) 30 …
3 particles each of mass m are kept at vertices of an equilateral triangle of side L. The gravitational field at centre due to these particles is (a) Zero (b) 3GM/L2 (c) 9 GM/L2 (d) ( 12/√3) (GM/L2) Answer: …
The relation between λ,ηand K for a elastic material is (a) (1/η)=(1/3λ)+(1/9k) (b) (1/k)=(1/3λ)+(1/9η) (c) (1/λ)=(1/3k)+(1/9η) …
The ratio of two specific heats of gas CP/CV for argon is 1.6 and for hydrogen is 1.4. Adiabatic elasticity of argon at pressure P is E. Adiabatic elasticity of hydrogen will also be equal to E at the pressure …
The string of a simple pendulum is replaced by a uniform rod of length L and mass M. If the mass of the bob of the pendulum is m, then for small oscillations its time period would be (assume radius …